This card is repugnantly overrated. He's no waste of paper, of course, but he's not something that's totally unparalelled for its cost like Goyf, Dark Confidant, Stoneforge, JTMS. Some of those cards released at a much lower price than this and are far better in that they're irreplaceable. Not every deck of such type will want to run this, and some will even want to run more specific ETB effects instead. Examples?

@strider24seven: Not quite. This is much more narrow than Eternal Witness. You can throw Eternal Witness in almost any green deck and it will net you card advantage. This is only good for blue decks that are built around it. This is probably the better card in general but Eternal Witness is still an amazing card.